File gdb-testsuite-rust-fix-for-empty-array.patch of Package gdb

From 772b7c2a75f392589518a0ee17a48914f1395c67 Mon Sep 17 00:00:00 2001
From: "Rudnicki, Piotr" <piotr.rudnicki@intel.com>
Date: Wed, 12 Feb 2025 10:50:37 +0100
Subject: [PATCH 03/25] gdb, testsuite, rust: fix for empty array

For the Rust language, to avoid segmentation fault in case of an empty
array, do not try to copy any elements, but allocate and return
the empty array immediately.

With the command before the change, gdb crashes with message:

(gdb) set lang rust
(gdb) p [1;0]
Fatal signal: Segmentation fault

After the fix in this commit, gdb shows following message:
(gdb) set lang rust
(gdb) p [1;0]
$1 = []

Update the existing test case gdb.rust/expr.exp to verify the change.

Approved-By: Tom Tromey <tom@tromey.com>
---
 gdb/rust-lang.c                 | 2 +-
 gdb/testsuite/gdb.rust/expr.exp | 4 ++++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/gdb/rust-lang.c b/gdb/rust-lang.c
index d4cd8802fa5..8bec934983e 100644
--- a/gdb/rust-lang.c
+++ b/gdb/rust-lang.c
@@ -1455,7 +1455,7 @@ eval_op_rust_array (struct type *expect_type, struct expression *exp,
   if (copies < 0)
     error (_("Array with negative number of elements"));
 
-  if (noside == EVAL_NORMAL)
+  if (noside == EVAL_NORMAL && copies > 0)
     return value_array (0, std::vector<value *> (copies, elt));
   else
     {
diff --git a/gdb/testsuite/gdb.rust/expr.exp b/gdb/testsuite/gdb.rust/expr.exp
index 97db748abf6..ca01c5feb36 100644
--- a/gdb/testsuite/gdb.rust/expr.exp
+++ b/gdb/testsuite/gdb.rust/expr.exp
@@ -115,6 +115,10 @@ gdb_test "print \[1,2 3" "',' or ']' expected"
 gdb_test "print \[1 2" "',', ';', or ']' expected"
 gdb_test "print \[23\]" " = \\\[23\\\]"
 
+gdb_test "print \[0;0\]" " = \\\[\\\]"
+gdb_test "print \[1;0\]" " = \\\[\\\]"
+gdb_test "print \[0;1\]" " = \\\[0\\\]"
+
 gdb_test "print b\"hi rust\"" " = b\"hi rust\""
 # This isn't rusty syntax yet, but that's another bug -- this is just
 # testing that byte escapes work properly.
-- 
2.51.0